1. Field
The following description relates to an organic light-emitting diode.
2. Description of the Related Art
Organic light emitting diodes (OLEDs) are self-emission devices, which have advantages such as a wide viewing angle, a high contrast ratio, a short response time, and excellent brightness, driving voltage, and response speed characteristics, and capable of generation of multi-color images.
In a typical organic light-emitting diode, an anode is formed on a substrate, and a hole transport layer, an emission layer, an electron transport layer, and a cathode are sequentially formed in this stated order on the anode. In this regard, the hole transport layer, the emission layer, and the electron transport layer are organic films including organic compounds.
The operating principle of an organic light-emitting diode having such a structure is described below.
When a voltage is applied between the anode and the cathode, holes injected from the anode pass through the hole transport layer and migrate toward the emission layer, and electrons injected from the cathode pass through the electron transport layer and migrate toward the emission layer. The holes and the electrons are recombined with each other in the emission layer to generate excitons. Then, the excitons are transitioned from an excited state to a ground state, thereby generating light.